Explanation

IS-ISGR (Graceful Restart) is a high-reliability technology that supports the GR capability, enabling uninterrupted data forwarding. Other devices in the area will perform routing calculations based on the new link state database, resulting in routing interruptions or routing loops.
IS-IS GThe R process is completed by the cooperation of GR-Restarter and GR-Helper. GR-Restarter: A device that is capable of GR and needs to perform GR.
GR-Helper: A device that has the GR capability and assists the GR device to complete the GR function.
GR-Restarter must have the ability of GR-Helper. To implement GR, IS-IS introduces TLV No. 211 (Restart TLV) andT1, T2, T3 three timers.
GR After the Restarter receives the CSNP from the Helper, it starts to synchronize the LSDB.
IS-In the extension of the GR capability of IS, three timers are introduced, namely T1, T2 and T3.

Explanation
In A, it is not to modify the priority of isis, but to modify the priority of routing (may be the problemThis description is not accurate).
The 2.2.2.2/32 route learned by RTB in C is ISIS priority, and the priority is 15 acl in D rule5 matches
2.0.0.0/8 and can match 2.2.2.2/32
The filter-policy in B rejects all routes by default, not just filtering 2.2.2.2/32